Battery max charge rate question

Hi folks I’m got a board coming to me with this pack in it:

I wanted to check with them that it would be OK to use my 8A charger on it and they said best not to go over 3A with this pack or 5A at the most.
Looking at the datasheet for the Samsung 40T is does show a max charging rate of 6A:

…but I think they are confused because in a 12s3p configuration the max charging current should be 6A*3=18A which is way over the puny 8A my charger can put out.

Does that make sense?

the limitation comes from the current that the BMS can handle


Ask them what bms is in there and we can figure out what it can charge at. @PropulsionBoards

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Yeah I can’t really do that since they already said if I want to keep my warranty I can’t go over 5A.
So I can’t be like OK I won’t BUT IF I DID what’s the specs on that BMS?

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Warranty is only 90 days anyway so I can keep it to 5A at least for that long anyway and then I’ll ask em.

No worries, I’ll ask.
@PropulsionBoards what bms do you use in your packs?

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Oh. Hey propulsion boards is on this forum! Hi guys not going over 5A during my warranty period just to be clear!

Wink wink nothing to see here

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No seriously tho I’m not going to endanger my warranty for a measly 3A during that 90 days.

the thing is, even some 8A rated bms, will heat up quite a bit even just charging at around 6A. if propulsionboard is really using an 8A bms, then 5A is a reasonable current to ba safe


I’m going to be honest, I don’t understand why people need super fast chargers. I’m going to be using a 1.5 amp charger on a ~15Ah pack.

Plus as far as I’m concerned charging them fast is not good for them, unless this is merely a myth

I already have the 8A charger that’s all. I can set it to any volts and amps I like.
I would probably charge at 1A almost all the time anyway because if I’m not using the board again that day it doesn’t matter how fast it charges so might as well put as little strain on the batteries as possible.

For on-the-go is the only time I’d use one. At home, low and slow is the way to go.

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Low and slow that is the tempo.


Sounds like that takes forever to charge, some people ain’t got no time for that

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I held back on that, thank you :laughing:


They respond a lot on their YouTube channel or you can go on their site they respond pretty quickly when I have purchased stuff from them :call_me_hand:


Forget to plug in one time the night before and you’ll be cussing that 1.5A charger. Really need a mix or something adjustable.


Charging port is also a factor here. Not all 2.1 x 5.5 jacks are created equal and the all metal ones max out at 8-10a iirc